arXiv · 1108.0372
In Situ Measurements of Stress-Potential Coupling in Lithiated Silicon
Abstract
An analysis of the dependence of electric potential on the state of stress of a lithiated-silicon electrode is presented. Based on the Larch\'e and Cahn chemical potential for a solid solution, a thermodynamic argument is made for the existence of the stress-potential coupling in lithiated-silicon; based on the known properties of the material, the magnitude of the coupling is estimated to be ca. 60 mV/GPa in thin-film geometry. An experimental investigation is carried out on silicon thin-film electrodes in which the stress is measured in situ during electrochemical lithiation and delithiation. By progressively varying the stress through incremental delithiation, the relation between stress change and electric-potential change is measured to be 100 - 120 mV/GPa, which is of the same order of magnitude as the prediction of the analysis. The importance of the coupling is discussed in interpreting the hysteresis observed in potential vs. state-of-charge plots, and the role of stress in modifying the maximum charge capacity of a silicon electrode under stress.
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Vijay A. Sethuraman, Venkat Srinivasan, Allan F. Bower, Pradeep R. Guduru. 2011-08-01. In Situ Measurements of Stress-Potential Coupling in Lithiated Silicon. https://doi.org/10.1149/1.3489378
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